Process of extracting precious metals and other metals from ore.



UNITEDTATES PATENT OFFICE.

JOHN M. TIPPETT, OF COLORADO SPRINGS, COLORADO.

PROCESS OF EXTRACTING PRECIOUS METALS AND OTHER METALS FROM ORE.

No Drawing.

lowing is a specification.

This invention relates to a process for the treatment of'the ores of the precious metals (gold and silver) and has for its object the extraction of as large a proportion as possible of the precious metals contained in the ore and at the same time recovering any'base metals, such as copper, lead, zinc, iron, etc., Which may be present in the ore.

I have discovered that by following the procedure hereinafter'detailed, it is possible to accomplish oil flotation in a cyanid solution. By combining oil flotation with the. steps of the cyanid process, I have pro- 'duced a process of extracting which is more efficient and also more economical than previous methods of treating the ores of precious metals. The process is applicable to any gold or silver ores, and is particularly adapted to the treatment of ores from the Cripple Creek district in Teller county, Colorado.

In order that my invention may clearly be understood, I shall proceed to describe in detail a specific embodiment of it, as well as some modifications of the embodiment first described. It should be clearly understood, however, that my invention is by no of water. The ore and cyanid solution are then fed to a tube mill,-a.ball mill, a Chilian mill, or stamp, where the ore is finely com-- minuted.

While the ore andthe cyanid solution are passing into the mill an alkali or a mixture of alkalis is added to the ore. The amount of alkali depends upon the acidity of-the ore under treatment. It willvary from one-half Specification of Letters Patent.

particles present.

type.

Patented Aug. 14, 1917.

Application filed December 23, 1916. Serial No. 138,631.

pound to ten pounds per ton of ore. It is not necessary that any particular alkali be used, although I have found caustic soda (NaOH) preferable. Sodium carbonate (Na CO ),"or lime (CaO), or a mixture of the three alkalis mentioned, or any two of them, is satisfactory. The adding of the alkaliv or alkalis serves two purposes: It preventsthe cyanid from being consumed should the pulp become too acid on account of the acidity of the ore, and I have foundv it is of material assistance in effecting fio tation. I

As the ore and cyanidso-lution enter into the mill, I add a suitable flotation oil, the amount of which may vary from onehalf pound to four pounds per ton .of ore.

The ore, the cyanid solution, the alkalis and'the oil are mixed together in the grinding mill. The oil emulsifies during v the grinding and coats the sulfids and metallic After the grinding has reduced the ore to the degree of fineness usual for cyanid treatment, the mixture is drawn from the mill and additional cyanid solution of the same strength previously used is added, Tnaking the ratio of ore to solution one to three or one to four. ture is'then flowed to a flotation cell, such as the Callow pneumatic cell or the minerals separation cell, where a large portion of the richest and finest minerals, including both sulfids and metallic particles, are floated by the gas'bubbles produced in the mixture in the flotation cell and removed from the pulp as a concentrate. The minerals recovered by fine that table concentration cannot save them. These concentrates are very diflicult to treat in the cyanid solution if not removed. 7

I The tailings from the flotation cell are passed over gravity concentration tables, which may be of the well known Wilfley type. There the coarser particles-of mineral which flotation failed to recover are separated from the pulp.

The tailings from the concentration tables pass intothickening tanks of the Dorr The clear solution overflowing from thethickening tanks is treated with zinc to precipitate the gold and silver in the usual manner. The underflow from the thickeners, containing the pulp, flows toagitating tanks'of the sort usually used in connection with the cyanid process. After agitation,

The mixthe pulp may be passed through any recognized type of slime filter to remove the gold and silver solution from the ore. The so lution is then treated with zinc to precipitate the gold and silver contained in it.

Changes may be made in the details of the process described Without departing from my invention. For example, it is not necessary that the flotation oil be added to the ore before the ore enters the grinding mill. It may be added after the ore has been finely ground and emulsified by agitation, either in a mechanical oil flotation cell, or an agitation tank before reaching the flotation cell.

I claim as my invention 1. An improvement in the cyanid process for treating ores, comprising the step of separating out a portion of the values in the ore by flotation in the presence of the cyanid solution.

2. An improvement in the cyanid process for the treatment of ores, comprising mixing the ore with cyanid solution and oil,

and separating a portion of the values from the mixture by flotation.

3. An improvement in the cyanid process for the treatment of ores, comprising mixing the ore with cyanid solution and oil and alkali; emulsifying the oil in the presence of the ore, the alkali, and the cyanid solution; floating a portion of the values in the pulp by producing gas bubbles in the mixture, and removing the values floated.

4. An improvement in the cyanid process of treating ores, comprising mixing the are with an equal or greater amount of'cyanid solution, alkali sufiicient in quantity to counteract the acidity of the ore, and a quantity of oil amounting to a fraction of one per cent. of the ore; emulsifying the oil in the presence of the ore, the alkali and the cyanid solution; and producing gas bubbles in the mixture whereby a portion of the values are floated.

5. An improvement in the cyanid of treating ores, comprising mixing the ore with cyanid solution and oil, and flowing the resulting mixture to a grinding mill, and then to a flotation cell.

6. An improvement in the cyanid process of treating ores, com-prising mixing cyanid solution, oil, and alkali with the ore; and passing the resulting mixture to a grinding mill, and then to a flotation cell.

7. An improvement in the cyanid process of treating ores, comprising mixing the ore with an 'equal quantity of cyanid solution, alkali sufficient to counteract the acidity of the ore, and an amount of oil equal to a fraction of one per cent. of the ore; passing the resulting mixture through a grinding mil-l; adding additional cyanid solution;

and passing the mixture to a flotation cell.

8. A process for the treatment of ores, comprisin mixing the ore with c anid solution an oil, emulsifying the oi, passing the "mixture through a flotation cell Where a portion of the minerals are separated out and removed, passing the remaining mixture I over concentratin tables Where a further portion of the minerals are separated out, separating the solids remaining in the mixture from the solution, and precipitating the values dissolved in the solution.

JOHN M. TIP-PETT. 

